1. Field of the Invention
The present invention relates to a method and apparatus for controlling the movement of a virtual body, where the virtual body is a computer-based model that represents the human, or other, form in a computer-generated virtual environment.
The form taken by the virtual environment will depend on the intended use of the system and may, for example, comprise the interior of a building for an architectural modelling application, or urban or surreal landscapes for games or other applications, around which environment the virtual body controlled by the user is moved. In the following, the term "virtual environment" will be used for such virtual landscapes or situations: the term "physical environment" will be used to denote the `real-world` surroundings of the user, for example a room in which the user contacts the various hardware devices, such as a head-mounted display (HMD), which provide the interface to the virtual environment.
The terms "virtual body" and "physical body" should be construed accordingly.
2. Description of the Related Art
One example of a control device in the form of a haptic glove is described in International Patent Application WO92/18925 (W. Industries). Within the virtual environment (viewed for example via HMD) the users hand appears as a cursor which undergoes changes corresponding with movement and flexure of the users hand. Contact between the cursor and objects within the virtual environment is simulated by inflating cushion portions of the glove to give a sensation of touch. Whilst the haptic glove is useful for techniques such as hands-on molecular modelling, within a virtual world where the object is to provide a sense of visual realism for the user, the changeable cursor (and the lack of the rest of a body) can detract from the users feeling of immersion.
A far more complex system, for generating and processing synthetic real-time environments is described in International Patent Application WO95/11479 (Redmond Productions). In the system described, the user is placed in a closed physical environment within which all the interaction occurs. On first use, a detailed virtual body for the user is built up, the process making use of detailed position sensing means within the physical environment to form a `wire-frame` model of the users body. Onto the wire frame, the virtual body is built up to a high density image with shading and hidden surface removal using a library of stored male and female body parts of all shapes and ages. In order to provide stimuli to the user (in addition to stereo imaging and audio through an HMD), the closed chamber includes a number of interaction apparatuses including a variable resistance treadmill, tactile output devices (pixel-addressed banks of rods which can be pushed out to form shapes or surface textures) and a "cybercycle" vehicle simulator.
While this latter system may provide the user with a high degree of immersive realism, the processing power required to generate and animate the virtual body in addition to generating the virtual environment is extremely high.